Pad-steam cationization of textiles

ABSTRACT

Described are methods and systems for cationizing and dyeing a natural fiber-containing textile. The method includes a step of steam treating a textile padded with a base and cationizing agent in a defined temperature range (greater than 100° C. to less than 110° C.) and for a defined time period (1 min to 10 min). The cationizing agent in the presence of the base is capable of generating two epoxide groups. The cationization step in the presence of steam using the halogenated catonization agent of the invention facilitates improved dyeing.

TECHNICAL FIELD

The current disclosure pertains to processes and systems for thecationization of natural fiber-containing (e.g., cotton-based) textileswhich can be used to improve association of dyes with the cationizedtextile.

BACKGROUND

Textile dyeing is the process of applying pigments or dyes on textilematerials such as fabrics, yarns, and fibers. Desirably, the dyeingprocess is efficient and rapid, and provides the dyed textile with adesired degree of coloring, and resistance to fading and running of thedye (color fastness). Further, the dyeing process and the materials usedtherein preferably do not adversely affect the aspects of the textile,such as its flexibility, durability, and tactile properties likesoftness, smoothness, stiffness. Depending on the material of thetextile (e.g., natural, synthetic, or mixtures thereof) and desiredcoloring, various dye types are used.

Common dyes for cotton have a negative charge. However, in an aqueoussolution the surface of the cotton fiber has a neutral or mildlynegative charge due to the presence of hydroxyl groups of the cellulosicmaterial that constitute the cotton. Negatively charged dyes getrepelled by negatively charged cellulosic material resulting in less dyeuptake by the cotton. In order for the textile to be dyed, the surfaceproperties of the cotton fiber must be altered so the dye is notrepelled. Traditional dyeing of cotton-based textiles has involved useof a mixture of salts, alkali, and dyes to associate the dye with thematerial of the cotton fiber. Salt is commonly used in a dyebath toreverse the charge on the cotton fiber, and alkali is used to allow thedyes to react with and associate with the induced positively-chargedsurface of the cotton fiber. However, these traditional processes canconsume significant amounts of water, energy, and chemicals, which isundesirable.

As an alternative to salt and alkali treatment, processes that usecationic reagents to modify cotton fibers are known in the art. Cationicreagents with appropriate chemistries can react with chemical groups oncellulose to provide a permanent cationic (positive) charge on thesurface of the cotton fiber (“cationic cotton”). The positive surfacecharge on the cotton fiber allows it to associate with a greater varietyof dyes, and can also allow for a range of color variation (e.g., colordepth). Cationization processes for cotton-based textiles may alsoconsume less water, energy, and chemicals, making them desirable forindustrial scale operations.

One type of cationizing agent is 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHTAC) (e.g., see U.S. Pat. No. 7,201,778; Hashem,M., et al., Textile Res. J., 73:1017, 2003). CHTAC can be reacted withthe hydroxyl groups of cellulose in the presence of a base. In firststep, the CHTAC is dechlorinated to form the reactive intermediateepoxypropyl trimethyl ammonium chloride (EPTAC), and the epoxide groupof this compound can react with a deprotonated hydroxyl group ofcellulose, thereby covalently linking the cationic ammonium chloridegroup to the cellulose backbone through an ther linkage. However, thereis a competing reaction with water molecules which results in theepoxide group of EPTAC being hydrolyzed, and generating2,3-dihydroxypropyl trimethyl ammonium chloride (2,3-DHTAC), which is awaste product. As such, formation of 2,3-DHTAC is desirably minimized.Carrying out “batch” treatment of a textile in the presence of base andcationizing agent at low temperature and an extended period of time canallow better reaction of the cationizing agent with the fiber and canminimize formation of waste product, but such prolonged processing stepsare impractical for commercial operations.

Attempts to reduce use of chemicals like salts, alkali, and water forgenerating and dyeing cationic cotton are made to improve the dying oftextiles. Accordingly, the methods and systems of the current disclosureimprove cationization of textiles, such as textiles that include naturalfibers such as cotton, while reducing use of chemicals in the process.The cationized textile can then be used as an improved substrate in adyeing process to provide a textile with better color properties.

SUMMARY

The current disclosure provides methods and systems that facilitate thecationization of textiles that contain, or are derived from, naturalfibers, such as cotton. The process of the disclosure forms improvedcationized textiles that facilitate subsequent textile dyeing andimproves properties of the dyed textile, such as coloration.

Using a process as described herein, cationization of textiles can beperformed in a short period of time with good results and reduction inwaste. Hydrolysis of the cationizing agent is minimized and its reactionwith the textile is improved. Subsequent dyeing of the cationizedtextile provides desirable coloration and color fastness. In turn, theprocess improves use of reagents by creating less waste products, savesenergy by minimizing processing times, and improves overall industrialprocessing efficiency. Further, the cationizing agent of the disclosure,which is capable of generating two epoxide groups in the presence of thealkali metal hydroxide, when used in conjunction with the cationizationmethods described herein, can provide better cationization on thetreated textile as compared to monohalogenated compounds.

In one aspect, the disclosure provides a method for cationizing atextile including a natural fiber or derivative thereof. The methodincludes a step of treating a textile including a natural fiber orderivative thereof with an aqueous solution that includes an alkalimetal hydroxide and a cationizing agent comprising a halogenatedcompound capable of generating two epoxide groups in the presence of thealkali metal hydroxide. Next, the textile is treated in an environmentwith steam at a temperature(s) that is greater than 100° C. but lessthan 110° C. for a period of time in the range of 1 min to 10 min toreact the cationizing agent with the textile.

In embodiments, the textile is heated to a temperature in theenvironment with steam, or more than one temperature, in the range ofgreater than 100° C. to less than 105° C., for a period of time in therange of about 2 to 8 minutes.

In embodiments, the textile is heated to a temperature in theenvironment with steam, or more than one temperature, in the range ofgreater than 100° C. to less than 104° C., for a period of time in therange of about 3 to 7 minutes.

In embodiments, the textile is heated to a temperature in theenvironment with steam, or more than one temperature, in the range ofgreater than 100° C. to less than 103° C., for a period of time in therange of about 4 to 6 minutes.

In some embodiments, after the textile is treated with the aqueoussolution that includes the alkali metal hydroxide and the cationizingagent, a portion of the aqueous solution is mechanically removed fromthe textile.

In some embodiments, the steps of treating with an aqueous solution andmechanically removing are performed at a temperature(s) of less than 35°C., and for a total period of time not greater than 1 minute.

In some embodiments, the steps of treating with aqueous solution,mechanically removing, and treating the textile in an environmentcomprising steam can be performed for a total a period of time of notmore than 11 minutes, such as in the range of 1 minute to 11 minutes, inthe range 1 minute to 8 minutes, or in the range 1 minute to 8 minutes,which significantly enhances textile throughput, while at the same timeproviding good cationization of the textile and incorporated nitrogencontent, which in turn facilitates a subsequent dyeing process.

In some embodiments, after steam treatment the textile is thenneutralized with an acid-containing solution. The cationic textile cansubsequently be dyed in a composition comprising a dye, using the samesystem that is used for padding and steam treatment, or can be dyedusing a different system.

An exemplary halogenated cationizing agent capable of generating twoepoxide groups in the presence of alkali metal hydroxide is a bis etherhalogenated di-hydroxylated ammonium compound such asbis[(3-chloro-2-hydroxypropyldialkylammonium)alkyl] ether dichloride. Inembodiments, the solution has an alkali metal hydroxide to cationizingagent molar ratio of greater than 1:1, such as in the range of 1.8:1 to5:1, or 2.0:1 to 4.5:1. Such bis-based compounds are preferred when usedin conjunction with the methods of the disclosure as they are able topromote cationization and dyeing with significantly reduced chemicals,water, energy, and wastewater generation, while at the same timefacilitating the formation of dyed textiles that have desirably bright,bold, and long lasting colors.

In another aspect, the disclosure provides a system for cationizing anddyeing a textile including a natural fiber or derivative thereof. Thesystem includes a padding bath configured to allow treatment of atextile including a natural fiber or derivative thereof with an aqueoussolution in the padding bath, the solution including an alkali metalhydroxide and a cationizing agent. The system also includes a steamtreatment apparatus configured to treat the padded textile, at atemperature(s) that is greater than 100° C. but less than 110° C. for aperiod of time in the range of 1 min to 10 min to react the cationizingagent with the textile.

In further embodiments, the system can also include a solution removalapparatus to remove aqueous solution from the padded textile aftertreatment in the padding bath, with the system including a conveyorapparatus capable of moving the textile through the padding bath and thesolution removal apparatus in about a minute or less. The system canalso include a neutralization bath to neutralize the textile with anacid-containing solution. The system can include a process controller,such as a computer-based controller, which can be programmed to performthe treatment method as described herein. Optionally, the system caninclude a dye bath for dyeing the cationized textile.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an exemplary system for cationization anddyeing of a textile.

FIG. 2 is a graph of nitrogen content on cationized cotton as preparedby a cold batch process versus treatment using different steamingconditions and base to cationizing agent ratios.

DETAILED DESCRIPTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art canappreciate and understand the principles and practices of the presentinvention.

All publications and patents mentioned herein are hereby incorporated byreference. The publications and patents disclosed herein are providedsolely for their disclosure. Nothing herein is to be construed as anadmission that the inventors are not entitled to antedate anypublication and/or patent, including any publication and/or patent citedherein.

The term “about” used preceding any numerical value of the disclosure orappended claims allows some slight imprecision in that stated numericalvalue, which imprecision may either be understood in the art, or mayresult from methods of measuring to obtain such numerical values (e.g.,such as with chemical or physical measurements), and any numerical valuenot preceded by the term “about” of the disclosure or appended claimsmay also be understood the same way.

Methods and compositions of the disclosure described as “comprising” or“including” can include those recited step and compounds, respectively,and optionally can include other steps and components. If methods orcompositions of the disclosure are described as “consisting of” thosemethods or compositions have the recited steps or compounds but do notinclude steps or compounds that are not recited. The term “consistingessentially of” generally refers to compositions that include therecited compounds and may include other non-recited compounds, but inunsubstantial amounts. For example, such compositions can include one ormore other non-recited components but not in an amount that is greaterthan about 1% (wt), greater than about 0.5% (wt), or greater than about0.1% (wt), of the total composition. Ina composition “consisting of” therecited components there is no other measurable amount of componentother than the recited component, or a method “consisting” of certainsteps includes no other steps than those ones recited.

The present disclosure describes methods and systems for cationizing atextile that includes a natural fiber, such as cotton, or derivativethereof. The cationization process can be carried out in a relativelyshort time period, wherein the process generates low levels of waste anduses minimal energy. The method and system treats the textile in anaqueous solution (which can also be referred to as a “padding” solution)that includes an alkali metal hydroxide and a cationizing agent that isa halogenated compound capable of generating two epoxide groups in thepresence of the alkali metal hydroxide, wherein the padding treatmentcan be performed quickly, such as in a period of not greater than aminute, and at temperatures, such as ambient temperatures, that do notrequire heating of the aqueous solution. After padding, excess solutionis removed from the textile, and then the textile is introduced into asteam heating apparatus to cause reaction of the cationizing agent withthe textile. The steam treatment is also performed rather quickly and ina defined temperature range. In particular, the textile is treated in anenvironment with steam at a temperature(s) that is greater than 100° C.but less than 110° C. for a period of time in the range of 1 min to 10min. In some embodiments more specific temperature and time ranges canbe used.

Advantageously, good cationization is achieved without requiring longpadding and reaction times (such as periods of time of hours)characteristic of cold batch padding processes. Instead, it has beendiscovered that the treatment temperatures and times of the disclosureprovide good cationization of the textile while minimizing loss ofreagent through hydrolysis. As an additional benefit using theprescribed steam treatment time and temperature, the aqueous paddingsolution requires less alkali metal hydroxide than typically used for amono-halogenated compound (as based on reactive groups).

The cationization method of the disclosure renders the textile inexcellent condition for association with a dye, and the dyeing processcan in turn provide good coloration of the textile. Textile dyeing canbe performed using a different system, or with the same system used forpadding and steam treatment as described herein.

A “system” according to the disclosure includes apparatus (“systemmembers”) that allow methods of the disclosure to be performed. Thesystem can include one or more of the following apparatuses: baths tohold treatment solutions (padding bath, wash bath, neutralization bath,and/or optionally dyeing bath); textile movement apparatus, such as aconveyor including rollers; solution removal apparatus, such as rollerpairs; steaming apparatus, including steam generator, heater, valving;control apparatus, such as a computer-based operation unit.

Steps of the method of the invention can be carried out using acontinuous process, a semi-continuous process, a batch process, or acombination thereof.

One option for processing the textile is using a continuous process. Acontinuous process is a flow product method that is used to manufacture,process, or produce an article avoiding stoppage of the processing flow.In a continuous process, an article that is being processed ormanufactured is in motion. In the continuous processing of a textile,the textile is often in the form of a sheet that is moved through two ormore processing areas (e.g., “treatment zone(s)”, with the sheet beingsubjected to different chemical, mechanical, and/or physical processesin each processing area while it is being moved. Movement of the textilein a continuous process can be facilitated using a system apparatus suchas a textile conveyor having rollers, which contact and facilitatemovement of the textile in a continuous process. A continuous processcan be performed on a system of the disclosure as described herein.

In embodiments, two or more steps of the method of the disclosure can bedescribed as a continuous process. For example, in steps of padding thetextile in a solution of the base and cationizing agent, mechanicallyremoving a portion of the solution from the padded textile, and thensteam treating the textile, the textile can be continuously movedthrough treatment zones which provide prescribed treatments of thetextile in motion. Other steps in the process of cationizing and dyeing(e.g., washing, neutralizing, and/or dyeing) can also be described ascontinuous, or optionally as non-continuous. FIG. 1 illustrates a systemthan can be used for the continuous processing of a textile according tomethods of the disclosure.

A semi-continuous process can include those wherein a flow productoperation (continuous) is stopped and then restarted after a period oftime. In some embodiments, two or more steps of the method of thedisclosure can be described as a semi-continuous process. For example,depending on desired processing conditions, movement of the textile canbe stopped in a treatment zone for a period of time and then restartedto move the textile out of the treatment zone. Methods of the disclosurecan use a semi-continuous process wherein movement of the textile isstopped in the steam treatment apparatus for a period of time andtemperature described herein suitable for reaction of the cationizingagent with the textile, and then movement of the textile is restartedafter the time period to move the textile out of the steam treatmentapparatus. A semi-continuous process can be performed on a system of thedisclosure as described herein.

Optionally, in embodiments, one or more steps in the method of thedisclosure can be performed in a batch process. For example, before aprocessing step of the disclosure, or after a processing step of thedisclosure, the textile can be altered in a way such that it isconfigured for use in a batch process rather than a continuous process.Alteration may be performed by cutting the textile to provide textileportions which are then used in one or more batch processing steps. In abatch process, the system can include apparatus configured in a waywhere the textile is not automatically moved from one apparatus to theother otherwise associated with apparatus of a continuous process. Forexample, in a system that includes apparatus for batch processingstep(s), system features such as a conveyor apparatus which otherwisetransports the textile from one apparatus to another in a continuousprocess may not be present in at least some of the apparatus of a systemused for batch processing. In embodiments of the disclosure a textile isprovided and then processed according to steps as described herein. Theterm “textile” refers to a flexible material that includes a network offibers and that is intended to encompass all forms of textile-basedarticles, including woven textiles, knitted textiles, and non-woventextiles. Textiles can be in the form of sheets (fabrics) or thinstrands (yams). Textiles can be formed by art-known techniques involvingone or more processes of weaving, knitting, crocheting, felting, orbraiding strands of fiber-containing materials together. Exemplarytextile substrates can be provided in the form of a textile roll whichprovides a continuous sheet of textile which may have a width of greaterthan 1 meter and a length of up to 100 meters or more. With reference toFIG. 1 , the arrangement of textile roll 10 to be treated, in relationto other components of the system, is illustrated.

Textiles that are cationized using the cationizing agent and steamtreatment according to methods of the disclosure include a natural fiberor derivative thereof. A natural fiber of the textile can be obtainedfrom plants such as cotton, hemp, ramie, flax, jute, kapok, coir,bamboo, and the like. Plant raw fibers can be spun to produce longstrands, and the strands can be included in the textile by weaving(interlacing of the strands), knitting (interlooping of the yarns),etc., as known in the art of woven fabrics. In nonwovens, theplant-based fibers are not converted into strands or yarns but arerather directly intermingled with each other or other fibers to producenon-woven fabrics.

The natural fiber in the textile material can include natural polymerssuch as naturally-occurring polysaccharides like cellulose or cellulosicmaterial, or chitin, or combinations thereof, or derivatives thereof.Cellulose or cellulosic material, which can include modified cellulose,as well as chitin and derivatives thereof, have chemistries that allowreaction with the cationizing agent. Cellulose is composed of repeatingglucopyranose subunits which presents three hydroxyl groups on eachsubunit. Chitosan is composed of repeating glycosamine subunits whichpresents two hydroxyl groups and one amine group on each subunit. Thehydroxyl groups of these polysaccharides are reactive with thehydroxide-activated cationizing agent.

Cellulosic materials also include rayon (viscose), which is generatedfrom wood pulp, and lyocell (e.g., Tencel™), which is a form of rayon.Textile substrates treated according to the disclosure can also includecellulose derivatives such as cellulose acetate, orimidazolidinone-modified cellulose.

The textile can be a blend or mixture of different materials, such as ablend of natural and synthetic fibers. Blends include blends ofdifferent types of natural fibers, such as wool/cotton blends,silk/cotton blends, and angora/cotton blends. Animal-based materials caninclude collagen fibers, keratin fibers, fibroin fibers, or a mixturethereof. Other exemplary blends include blends of cellulosic andsynthetic fibers, such as cotton/polyester blends, cotton/polyolefinblends, cotton/polyacrylonitrile blends, cotton/polyamide blends (e.g.,cotton/nylon blends), as well as blends of cellulose fibers andcellulose derivative fibers, such as cotton/rayon blends.

If the textile includes a blend of fibers, it preferably has at leastabout 5% (wt) of a natural fiber such as cotton, or derivative thereof,and more preferably about 25% (wt) or greater, about 35% (wt) orgreater, or about 40% (wt) or greater, of the natural fiber (e.g.,cellulosic), or derivative thereof. Exemplary blends include a naturalfiber (or derivative thereof; e.g., cellulosic)) to synthetic fiberweight ratio in the range of about 5:95 to about 95:5, 25:75 to about25:75, or 40:60 to about 60:40.

The woven textile can also be described in terms of textile weight(weight/area) which is often expressed in terms of ounces per squareyard, or grams per square meter. Textile weight can be affected by thetype or types of fibers in the textile and their properties, the type ofweave of the textile, and the finish of the textile. Exemplary textileweights typically range from about 50 g/m² to about 1000 g/m², or about100 g/m² to about 750 g/m².

In embodiments, the process of the disclosure utilizes a bleachedtextile, or the process further includes a process step of bleaching thetextile. A bleached textile can have removed from it natural color,odor, and impurities otherwise present in when the fiber of the textileis in a raw (natural) form. Oxidative bleaching is typically performedusing oxidative bleaching agents such as hydrogen peroxide, sodiumhypochlorite, sodium chlorite, sulfuric acid, or a combination thereof.Sodium hydrosulphite is often used for reductive bleaching of textiles.

If an optional bleaching step is performed, the textile can be placed ina bleaching bath for treatment with a bleaching solution for a desiredperiod of time. An exemplary bleaching solution includes hydrogenperoxide or sodium hypochlorite in an aqueous solution at aconcentration in the range of about 0.5 to 5.0% (wt). After bleaching,the textile can be washed and dried.

The method of the disclosure includes a step of treating the textilewith an aqueous treatment solution comprising an alkali metal hydroxide(base) and a cationizing agent.

Treatment of the textile with a solution including base and cationizingagent can be referred to as a “padding” process in which the aqueoussolution with the treatment compounds (treatment solution, or paddingsolution) are placed in contact with the textile. Often, the treatmentsolution is present in a container (e.g., a “padding bath” or simply a“padder”) into which the textile is submerged. In the padding bath thetextile can become saturated with the treatment solution. The base andcationizing agent come into contact with material of the textile (and ina subsequent process step the activated cationizing agent is reactedwith the textile in the presence of steam). Alternatively, the aqueoustreatment solution can be applied using a spray apparatus, a roller, ora brush. Generally, padding is performed for a short period of time,such as not greater than one minute.

A cationizing agent, as used herein, refers to a compound that is ableto associate with the textile material, such as by chemical reactionresulting in covalent bonding between the agent and material of thetextile. The reaction imparts a positive (cationic) charge to thetextile.

Exemplary cationizing agents include halogenated and hydroxylatedammonium compounds. In the presence of a base, the compound can becomedehalogenated and deprotonated to form a reactive glycidyl (epoxy)intermediate compound which in turn can react with hydroxyl groups ofcellulosic material in the textile. Amine groups of chitosan-containingtextiles can also be reacted with glycidyl-containing ammonium compoundsto provide cationization to the textile. Methods and systems of thedisclosure use a halogenated compound capable of generating two epoxidegroups in the presence of an alkali metal hydroxide.

Exemplary cationizing agents include bis ether di-halogenateddi-hydroxylated ammonium compounds, such as those of the followingformula I:

wherein R¹ and R^(1′) are independently selected from alkylene(divalent) groups, such as a C1-C6 alkylene groups like methylene,ethylene, propylene, etc., and R², R^(2′), R³, and R^(3′), areindependently selected from alkyl (monovalent) groups, such as a C1-C6alkyl groups like methyl, ethyl, propyl, etc., and R⁴ and R^(4′) areindependently selected from alkylene (divalent) groups, such as a C1-C6alkylene, and X-X′″ are independently selected from halogen atoms, suchas Cl, Br, or I.

In some embodiments the halogenated hydroxylated ammonium compound is abis[(3-chloro-2-hydroxypropyldialkylammonium) alkyl]ether dichloridecompound. R¹ and R^(1′) are methylene, and preferably R², R^(2′), R³,and R^(3′) are independently selected from methyl, ethyl and propyl, andR⁴ and R^(4′) are preferably methylene, ethylene, or propylene.Exemplary compounds includebis[(3-chloro-2-hydroxypropyldimethyhummonium)ethyl]ether dichloride,bis[(3-chloro-2-hydroxypropyl-dimethylammonium)ethyl]ether dichloride,and bis[(3-chloro-2-hydroxypropylmethylethyl-ammonium)propyl]etherdichloride. See, for example, U.S. Publication No. 2015/0210627.

In embodiments, the treatment solution includes desired types andamounts of base and cationizing agent which facilitate rapid downstreamprocessing in a steaming step, described herein. In embodiments, theconcentration of the cationizing agent in the aqueous treatment solutionis at least about 20 g/L but preferably not greater than 125 g/L.Preferably, the concentration of the cationizing agent in the aqueoustreatment solution is in the range of about 40 to about 105 g/L, about50 to about 95 g/L, or about 55 to about 85 g/L.

The concentration of cationizing agent can also be expressed in terms ofmolarity. For a dihalogenated cationizing agent, the concentration inthe aqueous treatment solution can be at least about 0.05 molar.Preferably, the concentration of a dihalogenated cationizing agent is inthe range of about 0.05 molar to about 0.3 molar, about 0.1 molar toabout 0.25 molar, about 0.125 molar to about 0.225 molar, or about 0.14molar to about 0.2 molar.

Advantageously, by applying the prescribed steam treatment time andtemperatures, the aqueous padding solution generally requires lesssolids reagents than what is often used when mono-halogenated compoundsare used for cationization. In particular, the process requires lessalkali metal hydroxide, which is beneficial as it reduces waste andincreases economic efficiency of the dyeing process.

Exemplary alkali metal hydroxide bases are potassium hydroxide andsodium hydroxide. The amount of base used can be determined by theamount of cationizing agent, and the steam treatment time andtemperature. In embodiments, the concentration of the base in theaqueous treatment solution is at least about 10 g/L but preferably notgreater than 40 g/L. Preferably, the concentration of the base in theaqueous treatment solution is in the range of about 15 g/L to about 35g/L, or about 15 g/L to about 30 g/L. Expressed in terms of molarity,when used with the dihalogenated cationizing agent, the concentration ofthe base in the aqueous treatment solution can be at least about 0.25molar, or at least about 0.35 molar. Preferably, the concentration ofthe base when a dihalogenated cationizing agent is used is in the rangeof about 0.30 molar to about 1.0 molar, about 0.35 molar to about 0.9molar, or about 0.40 molar to about 0.8 molar.

The amounts of base and cationizing agent in the treatment solution canalso be described with reference to the molar ratio of the base to thecationizing agent. In embodiments, the aqueous solution can have a molarratio of alkali metal hydroxide to di-halogenated cationizing agent ofgreater than about 1:1, or greater than about 1.8:1, but less than about5:1. In preferred aspects, the molar ratio of the alkali metal hydroxideto the cationizing agent is in the range of about 1.8:1 to about 5:1,about 2.0:1 to about 4.75:1, or about 2.25:1 to about 4.5:1.

In some modes of practice the aqueous treatment solution furtherincludes a viscosity enhancer (also referred to as an “anti-migrationagent”). According to the disclosure use of a viscosity enhancer canimprove immobilization of the cationizing agent in the padded textile,which in turn improves reaction efficiency, and then subsequent dyeingof the cationized textile. Exemplary viscosity enhancers includepolyvinyl methyl ethers (e.g., having a mean molecular weight of about100,000), sodium alginates, Gaur gum, carboxymethylcellulose (CMC), lowmolecular weight cellulose ethers, polyethylene glycols (e.g., having amean molecular weight in the range of 8,000 to 10,000), poly vinylcaprolactam, and acrylic polymers, with acrylic polymers being apreferred viscosity enhancer. Preferred viscosity enhancers should notdisturb the dye, should not cause loss in color brilliance, should haveadequate liquor stability, should not cause any hardening of the handle,should have good solubility at room temperature, and should provide goodeffects in small amounts. In embodiments, the viscosity enhancer isprovided to the padding bath to provide a viscosity in the range ofabout 50 to about 350 cP. In exemplary embodiments, the viscosityenhancers can be used in an amount in the range of about 2% to about 20%(wt), or about 5% to about 10% (wt) in the aqueous padding solution.

The aqueous padding solution is generally maintained at a temperature(or temperatures) not greater than 35° C. Preferably the aqueous paddingsolution is at a temperature(s) in the range of about 15° C. to about27° C., or about 18° C. to about 25° C.

In some exemplary modes of practice the method is a continuous processwherein the textile is fed into a treatment bath, the textile is movedthrough the bath, and then exits the bath. In embodiments, the paddingstep can be performed quickly Referring to FIG. 1 , a sheet 12 oftextile is advanced from textile roll 10 and into padding bath 20 whichholds treatment solution 22 including cationizing agent and base.Padding bath 20 includes roller set (24 a-24 c) to facilitate movementand positioning of the advancing textile sheet in the treatment solution22. The residence time (“padding times”) in the padding bath is definedby the time where a particular portion of the textile enters the bathand then ends when that particular portion leaves the padding bath.Typically, this is greater than 0.5 second, greater than 1 second, orgreater than 2 seconds, and generally less than 1 minute, about 45seconds or less, or about 30 seconds or less. An exemplary padding timeis in the range of 1 second to 1 minute, 1 second to 45 seconds, 1second to 30 seconds, 1 second to 20 seconds, 1 second to seconds, 1second to 10 seconds, or 2 seconds to 5 seconds.

In embodiments, the residence time of the textile in the padding bathcan be determined by the speed of the machine as well as other aspectsof the system. For example, based on the rate that the textile conveyorapparatus of the system moves the textile though a treatment area, andthe length of the travel path through the treatment area, the residencetime of the textile in the treatment area can be known. In exemplarysystem, the textile conveyor apparatus moves the textile through atleast the padding bath at a rate in the range of about 20 meters/min toabout 50 meters/min. Exemplary lengths of travel paths through thepadding bath can be in the range of about 0.5 meter to about 5 meters,or about 1 meter to about 4 meters.

The padding process can result in the textile becoming “soaked” or“saturated” with the treatment solution. In some modes of practice, asthe textile exits the bath excess treatment solution can be removed fromthe textile and returned to the padding bath.

Referring to FIG. 1 , the textile can be advanced out of the treatmentsolution 22 and through roller pair (26 a, 26 b) which applies pressureto the padded textile to remove excess treatment solution, which isreturned to the padding bath 20. However, sufficient treatment solutionis maintained in the textile to provide an amount of base andcationizing agent for reaction with the textile in the subsequent steamtreatment step.

The padded textile can be described in terms of the amount of aqueoustreatment solution present in the textile (an “effectiveconcentration”). For example, the padded textile can be referred to interms of a “wet pickup,” which is the amount (weight) of treatmentsolution present in the textile divided by the weight of dry textilebefore padding. Generally, the padding step provides a wet pick up ofthe treatment solution of greater than about 50%. Preferably, thepadding step provides a wet pick up of the treatment solution in therange of about 60% to about 80%. In an exemplary scenario, if thecationizing agent is present in the padding bath at 100 g/L, and them is70% wet pick up, then the effective concentration of the cationizingagent in the textile is 70 g/L, or 7%.

Generally, the padding process and removal of any excess treatmentsolution from the saturated textile can be performed rather quickly,which facilitates the overall process of cationization and dyeing of thetextile.

After the textile has been padded, it is introduced into an apparatusthat applies steam energy to the padded textile to promote reaction andbonding of the cationizing agent to the textile. Referring to FIG. 1 , asheet 12 of textile is advanced from roller pair (26 a, 26 b) intosteaming apparatus 30 through opening 32. Steaming apparatus 30 includesroller set (34 a-34 e) on which the textile can be supported and movedthrough the steam chamber. The apparatus can also have a steam generator(not shown) which includes a water vessel and a heating element capableof heating a volume of water to boiling to generate steam which isintroduced through a conduit (not shown). The chamber can also have aheating element (not shown) to maintain a steam-containing atmosphere ata desired temperature according to the disclosure. The steam treatmentstep is carried out for a short period of time in a well-definedtemperature range.

The steam process can be described with regards to the steam density inthe steam chamber. The density of steam is dependent on the temperatureof the steam and the size of its container, or the pressure it is under.At 100° C. at normal atmospheric pressure steam (i.e., dry steam) has adensity of 0.0006 grams per cubic centimeter (600 g/m). In the method ofthe disclosure the steam density in the chamber is at least 0.0006g/cm³. However, the steam chamber will typically include dry steam,wherein all water molecules are in the gaseous state, and also wetsteam, where some of the water molecules have lost their energy andcondense into airborne water droplets. Optionally, steam used in themethod of the disclosure can be referred to by the dryness fraction ofwet steam. For example, if the water content in the steam is 5% by mass,then the steam is said to be 95% dry with a dryness fraction 0.95. Bycomparison, it is noted that under normal atmospheric conditions, amaximum of about 30 grams of water vapor can exist in a cubic metervolume of air with a temperature of about 35° C.

Upon introduction to the steam chamber, the padded textile is rapidlyheated to the steam temperature set for the apparatus. Generally, thetextile will be heated to the desired temperature in a short period oftime, such as less than 15 seconds or less than 10 seconds. The textilemay be moved through the steam chamber as it reaches the desiredtemperature.

The textile is heated to a temperature in the steam chamber, or morethan one temperature, that is at least 100° C., but less than 110° C.,and then held at this temperature(s) for a period of time in the rangeof 1 min to 10 min to react the cationizing agent with the textile.

Preferably, the textile is heated to a temperature in the steam chamber,or more than one temperature, in the range of: greater than 100° C. toabout 109° C., greater than 100° C. to about 108° C., greater than 100°C. to about 107° C., greater than 100° C. to about 106° C., greater than100° C. to about 105° C., greater than 100° C. to about 104° C., orgreater than of 100° C. to about 103° C. Preferably, the textile istreated at a temperature(s) in any one of these ranges in steam for aperiod of time in the range of about 1 to about 10 minutes, about 1 toabout 9 minutes, about 2 to about 8 minutes, about 2 to about 7 minutes,about 3 to about 7 minutes, about 3 to about 6 minutes, or about 4 toabout 6 minutes.

An exemplary heating temperature and treatment time is where the textileis heated to a temperature in the steam chamber, or more than onetemperature, in the range of greater than 100° C. to about 105° C., fora period of time in the range of about 2 to about 8 minutes.

Another exemplary heating temperature and treatment time is where thetextile is heated to a temperature in the steam chamber, or more thanone temperature, in the range of greater than 100° C. to about 104° C.,for a period of time in the range of about 3 to about 7 minutes.

Another exemplary heating temperature and treatment time is where thetextile is heated to a temperature in the steam chamber, or more thanone temperature, in the range of greater than 100° C. to about 103° C.,for a period of time in the range of about 4 to about 6 minutes.

The steam treatment temperatures and times of the disclosure can promoterapid reaction of the cationizing agent with reactive chemistries on thetextile while minimizing hydrolysis of the cationizing agent, whichotherwise renders it nonfunctional.

Optionally, the treated textile can be described in terms of a reactionefficiency of the cationizing agent with the textile. Reactionefficiency can by expressed by the amount of cationizing agent reactedper weight unit of the textile (e.g., mmol cationizing agent per gram oftextile material). The reaction efficiency (cationization degree) can bedetermined by the amount of nitrogen content of the textile as impartedby the cationizing agent. For example, the process of the disclosureprovides at least about 0.075 mmol nitrogen (from the cationizing agent)per gram of textile. More typically there is at least about 0.085 mmol,at least about 0.09 mmol, or at least about 0.095 mmol nitrogen (fromthe cationizing agent) per gram of textile. Determination of reaction ofcationizing agent can be determined by analyzing the added ammoniumgroups to the textile such as by Kjeldahl method or combustion method(e.g., see Schwarzinger, C., et al. (2002) Monatshefte fur Chemie133:1-17; or Ma, W., et al. (2017) Molecules, 22:2235).

After the cationized textile has been steam treated, it can be washedwith a hot aqueous solution. The hot water wash can remove at least aportion of any unreacted or hydrolyzed cationizing agent, base, and/orother optional component (e.g., viscosity enhancer) carried over fromthe padding bath. For example, in a continuous process, thesteam-treated textile can exit the steaming apparatus 30 through anaperture 36, and can be fed into a hot water bath 40. Hot water bath 40includes roller set (44 a-44 e) to facilitate movement and positioningof the advancing textile sheet in the hot water.

The hot aqueous solution can have a pH in the range of 6-8. Thetemperature of the hot water bath is preferably in the range of about70° C. to about 90° C., or even more preferably in the range of about75° C. to about 85° C. The cationized textile can be maintained in thehot aqueous bath for a period of time less than 20 min, less than 15min, such as a time in the range of about 5 to 15 minutes. In acontinuous process the textile can be moved through the bath, such as onrollers in the bath, and then the textile can exit the bath after thedesired period of washing. The washed textile can be transferred to aneutralization bath without removing water from the textile.

After the cationized textile has been hot water washed, it can beneutralized by treatment with an acid. The acid can react with anyremaining base present in the textile, thereby neutralizing thecationized textile. For example, in a continuous process and withreference to FIG. 1 , the washed cationized textile can exit the hotwater bath 40, can be mechanically treated, such as by passage through aroller pair (not shown) to remove the hot water solution, and then canbe fed into a neutralization bath 50 including an aqueous compositionwith an acid. The neutralization bath 50 can include roller set (54 a-54e) to facilitate movement and positioning of the advancing textile sheetin the acid-containing solution of the bath.

The acid-containing solution can have an exemplary pH in the range ofabout 4 to about 5. For example, the acid solution can be formed using aweak acid, such as acetic acid, citric acid, or oxalic acid, or acombination thereof. The amount of acid can depend on the acid typeused, but an exemplary acid is acetic acid at a concentration in therange of about 1 about 2 grams per liter. The acid treatment solution isgenerally maintained at a temperature (or temperatures) not greater than35° C. Preferably the acid treatment solution is at a temperature(s) inthe range of about 15° C. to about 27° C., or about 18° C. to about 25°C. The cationized textile can be maintained in the acid treatmentsolution for a period of time less than 20 min, less than 15 min, suchas a time in the range of about 5 to 15 minutes. In a continuous processthe textile can be moved through the acid treatment solution, such as onrollers in the bath, and then the textile can exit the acid treatmentsolution after the desired period of washing. Accordingly, a dyeing stepand dyeing apparatus may or may not be a part of the method and systemof the disclosure.

The system and method of the disclosure may optionally include one ormore steps of cold or hot water wash(es) between afterneutralization/acid treatment.

After the cationized textile has been neutralized, it can be dyed bytreatment with in a dye solution. The dyeing process can be performedusing the same system as the padding bath and steam treatment apparatus,or can be performed in a different system, separate from the paddingbath and steam treatment apparatus. If the dyeing process is performedusing a different system, such as in a dyeing facility at a differentlocation from the facility having the padding/steam treatment system,the cationized textile can be transported to that facility and dyed.

For purposes of discussing a step of dyeing the textile, reference toFIG. 1 showing a system with a dyeing bath is made. For example, in acontinuous process, the neutralized cationized textile can exit theneutralization bath 50, can be mechanically treated, such as by passagethrough a roller pair (not shown) to remove any excess acid solution,and then can be fed into a dye bath 60 including a composition with adye. The dye bath 60 can include roller set (64 a-64 e) to facilitatemovement and positioning of the advancing textile sheet in the dyesolution.

Cationized textiles can accept a variety of dyes and therefore providegood flexibility for color offerings. The cationized textile can provideimproved dye association by virtue of chemical interaction between thepositively-charged quaternized nitrogens of the textile boundcationizing agent and, for example, anionic groups of an anionic dye.However, the cationized textile can also accept other dye types thatassociate the dye with the textile in a way that does not rely on thetextile-bound cationizing agent.

A “dyeing” process is one that imparts color to a textile, and “dye”refers to any substance that provides color to a textile, which can alsoinclude pigments, as described herein. Dyes can be associated with afiber of the textile by chemical reaction, absorption, dispersion, or acombination thereof. Dyes typically differ in their resistance tosunlight, perspiration, washing, gas, and alkali; their affinity fordifferent fibers; their reaction to cleaning agents and methods; andtheir solubility and method of application. Exemplary dye types that canbe used to color the cationized textiles made using the methods andsystems of the disclosure include natural dyes, basic (cationic) dyes,direct (substantive) dyes, sulfur dyes, pigment dyes, vat dyes, reactivedyes, and acid dyes Reactive dyes can react with one or more chemicalgroups of the textile fiber.

Reactive dyes can be applied from alkaline solution or from neutralsolutions which are then alkalized in a separate process. Heat treatmentcan also be used during dyeing to develop different color shades. Afterdyeing, the textile can be washed with soap to remove any unfixed dye.Reactive dyes can be used for cationic textiles including cellulosefibers, as well as those including blends of wool, silk, nylon, andacrylics.

Direct dyes can color cellulose fibers directly without requiring theuse of a mordant (a dye fixative). Direct dyes can be used for cationictextiles including cellulose fibers, as well as those including blendsof wool, silk, nylon, rayon etc.

Sulfur dyes are water-insoluble and made soluble using a reducing agentand alkali pH (e.g., caustic soda and sodium sulfide). Dyeing is done athigh temperature with large quantities of salt so that the colorpenetrates into the fiber. After dyeing the textile is oxidized byexposure to air or by using chemicals to provide desired color shades.Excess dyes and chemicals can be removed by thorough washing. Sulfurdyes are fast to light, washing, and perspiration, and are mostly usedfor cotton and linen.

Vat dyes are insoluble in water and are typically made soluble byreduction in alkaline solution which allows them to be affixed totextile fibers. Subsequent oxidation or exposure to air restore the dyeto its insoluble form. An exemplary vat dye is Indigo. Vat dyes are thefastest dyes for cotton, linen and rayon. Vat dyes are commonly usedwith mordants to dye other textiles such as wool, nylon, polyesters,acrylics and modacrylics.

Pigments are not technically dyes, but still are used for coloringtextiles like cotton, wool and other manmade fibers due to theirexcellent light fastness. Pigments are typically affixed to fibers of atextile using resins. After dyeing, the textiles are subjected to hightemperatures. In some embodiments, a dyeing step according to thedisclosure can use a pigment to color the cationized textile. Naturaldyes, which are obtained from a natural source such as vegetable,animal, or mineral source, can be used with a cationized textiles.Direct printing is the most common approach to apply a color patternonto a textile. If done on colored textile, it is known as overprinting.The desired pattern is produced by pressing dye on the textile in apaste form. To prepare the print paste, a thickening agent is added to alimited amount of water and dye is dissolved in it. Earlier, starch waspreferred as a thickening agent for printing. More recently, gums oralginates derived from seaweed are preferred as they allow betterpenetration of color and are easier to wash out. Most pigment printingis done without thickeners because the mixing up of resins, solvents andwater produces thickening.

Some dyes used for dyeing cationized textiles include “reactive” oranionic dyes.

Reactive, anionic dyes can include one or more anionic groups, such assulfonate or carboxylate groups. For example, the anionic dye caninclude one or more sodium sulfonate (—S0 ₃Na) groups. The one or moreanionic groups can be present in a dye molecule cable of absorbing lightin the visible spectrum and having at least onechromophore/color-bearing group with a conjugated system. Commonly usedanionic dyes include those based on azo chemistries, anthraquinonechemistries, and triphenyl methane chemistries. Azo dyes are chemicallycharacterized by the group R—N═N—R′, where R and R′ commonly include anaryl group, with various chemical substituents attached to the arylgroups. Other anionic dyes include those having nitro chemistries, azinechemistries, and quinoline chemistries. Acid dyes are a type of anionicdyes that can include acid groups such as carboxylic acid, sulfonicacid, or phosphoric acid groups. Anionic dyes that can be used inmethods of the disclosure are described in various references, such asAspland, J. R., (1997) Textile Dyeing and Coloration, AmericanAssociation of Textile Chemists and Colorists, AATCC; Knutson, L. (1986)Synthetic Dyes for Natural Fiber, Interweave Press; Revised edition.Examples include those dyes named “Reactive,” “Direct,” and “Acid,”preceded or followed by a color name and a number and/or letter, such as“Reactive Blue 19,” “Direct Blue 71,” “Acid Blue 62,” “Reactive RedME4BL,” etc.

In some embodiments, the concentration of the anionic dye in the dyeingsolution is in the range of about 0.001 g/L to about 5.0 g/L, about 0.01to about 2 g/L, with more concentrated dye solutions providing a moreintense dye color to the textile. In embodiments, the anionic dyesolution is generally maintained at a temperature(s) in the range ofabout 30° C. to about 80° C. Dyeing can be carried out for a desiredperiod of time, such as in the range of about 30 minutes to about 60minutes. With reference to FIG. 1 , after dyeing the textile can bewashed (not shown) and then rolled to a roller 72.

Operation of one or more parts of the system can be controlled using aprocess controller (not shown), such as a computer-based controller,which can be programmed to perform the treatment method as describedherein.

Example 1 Rapid Pad-Steam Cationization and Dyeing of Cotton Fabric

A bleached cotton fabric (A4 size) was dipped in various solutionscontaining the cationizing agentbis[(3-chloro-2-hydroxypropyldimethylammonium)ethyl]ether dichloride(annotated as bis-CHPDMAEEDC) which is commercially available under thetradename ECOFAST™ Pure; Dow) and sodium hydroxide. Concentrations ofbis-CHPDMAEEDC and NaOH base are listed in Table 1.

The solutions were at ambient temperature (20° C.) and the fabric wasmaintained in the solutions for approximately 2-3 seconds before beingremoved. The soaked fabric was then passed through two rollers with 70%expression to squeeze the excess solution from the fabric. Accordingly,the effective concentration of the cationizing agent on the fabric was49 g/L (0.119 molar).

This was followed by steam treatment of the padded fabric at atemperature of 102° C. for varying periods of time (5 min., 10 min., 15min., 20 min.).

As a control standard, the cationizing agent and base (70 gplbis-CHPDMAEEDC and gpl NaOH) were padded onto A4 cotton fabric and thenleft to batch react at a low temperature (25° C.) for a period of 14hours.

After steam treatment, the cationized fabric was washed in hot water ata temperature of 80° C. for 10 min, then the washed fabric wasneutralized in a solution containing acetic acid (1.5 g/L) as per NaOHconcentration in ambient condition (temperature 30° C.) for 10 min.After cationization, nitrogen content on the fabric was assessed by thecombustion method.

Dyeing was performed by placing 2 gm of the cationized cotton in a dyecomposition including 3% Reactofix Red ME4BL dye solution and 15 g/Lsodium carbonate to improve the fixation and performance properties. Thedye solution was at a temperature 60° C. and the fabric was maintainedin the solution for 30 min. This was followed by washing process of acold wash and neutralization, a hot wash at 60° C. for 10 min, and thencold wash. Results of the rapid steam treatments were compared andstandardized against a cotton fabric prepared as the controlled standard(Table 1 and FIG. 2 ).

TABLE 1 Padding Sodium Molar Ratio Results hydroxide NaOH: Nitrogen DyeColoration (% (NaOH) Cationizing cationizing Content on strengthrelative to flakes agent agent Steam Treatment Fabric CBP standard) 11g/L 70 g/L 1.62:1 102° C. for 20 min 0.0765 0.27S molar 0.170 molar 13g/L 70 g/L 1.91:1 102° C. for 15 min 0.0875 74.60 0.325 molar 0.170molar 17 g/L 70 g/L  2.5:1 102° C. for 10 min 0.101 72.21 0.425 molar0.170 molar 28 g/L 70 g/L 4.11:1 102° C. for 5 min 0.11 75.96 0.7 molar0.170 molar

Surprisingly, the above results showed that using a bis-cationizingagent, a limited amount of base, short steaming times, and a steamtemperature near 100° C., there was good staining (as indicated by lessresidual color in bath), good nitrogen content on cotton, and good colorstrength.

1. A method for cationizing a textile including a natural fiber orderivative thereof, the method comprising treating a textile including anatural fiber or derivative thereof with an aqueous solution comprisingan alkali metal hydroxide and a cationizing agent comprising ahalogenated compound capable of generating two epoxide groups in thepresence of the alkali metal hydroxide; and treating the textile in anenvironment comprising steam at a temperature in the range of greaterthan 100° C. to less than 110° C. for a period of time in the range of 1min to 10 min to react the cationizing agent with the fabric.
 2. Themethod of claim 1, wherein the cationizing agent is a bis etherhalogenated di-hydroxylated ammonium compound.
 3. The method of claim 2wherein the cationizing agent has the formula:

wherein R¹ and R^(1′) are independently selected from alkylene groups,R², R^(2′), R³, and R^(3′), are independently selected from alkylgroups, R⁴ and R^(4′) are independently selected from alkylene groups,such as a C1-C6 alkylene, and X-X′″ are independently selected fromhalogen atoms.
 4. The method of claim 3 wherein R¹ and R^(1′) areindependently selected methylene, ethylene, and propylene, R², R^(2′),R³, and R^(3′), are independently selected from methyl, ethyl, andpropyl, and R⁴ and R^(4′) are independently selected from C1-C6alkylene.
 5. The method of claim 4 wherein the cationizing agent isbis[(3-chloro-2-hydroxypropyl-dialkylammonium)alkyl]ether dichloride. 6.The method of claim 1 wherein the textile is treated in steam at atemperature in the range of greater than 100° C. to less than 107° C.,greater than 100° C. to less than 106° C., greater than 100° C. to lessthan 105° C., greater than 100° C. to less than 104° C., or in the rangeof greater than 100° C. to less than 103° C.
 7. The method of claim 1wherein the textile is treated in steam for a period of time in therange of 1 to 10 minutes, about 1 to 9 minutes, about 2 to 8 minutes,about 2 to 7 minutes, about 3 to 7 minutes, about 3 to 6 minutes, orabout 4 to 6 minutes.
 8. The method of claim 1 comprising mechanicallyremoving a portion of the aqueous solution from the fabric aftertreating with the aqueous solution.
 9. The method of claim 8 wherein thesteps of treating with aqueous solution and mechanically removing areperformed at one or more temperatures of less than 35° C., and for atotal a period of time of not greater than 1 minute.
 10. The method ofclaim 9 wherein the wherein the steps of treating with aqueous solutionand mechanically removing are performed for a total a period of time ofnot more than seconds, not more than 30 seconds, in the range of 1second to 1 minute, 1 second to 45 seconds, 1 second to 30 seconds, 1second to 20 seconds, 1 second to 15 seconds, 1 second to 10 seconds, or2 seconds to 5 seconds.
 11. The method of claim 8 wherein the whereinthe steps of treating with aqueous solution, mechanically removing, andtreating the fabric in an environment comprising steam are performed fora total a period of time of not more than 11 minutes, not more than 10minutes, not more than 9 minutes, not more than 8 minutes, not more than7 minutes, or not more than 6 minutes, or for a period of time in therange of 1 minute to 11 minutes, 1 minute to 10 minutes, 1 minute to 9minutes, 1 minute to 8 minutes, 1 minute to 7 minutes, or 1 minute to 6minutes.
 12. The method of claim 1 wherein the aqueous solution has amolar ratio of the alkali metal hydroxide to the cationizing agent ofgreater than 1:1.
 13. The method of claim 12 wherein the molar ratio ofthe alkali metal hydroxide to the cationizing agent is in the range of1.8:1 to 5:1, or 2.0:1 to 4.5:1.
 14. The method of claim 1, wherein theaqueous solution further comprises a viscosity enhancer.
 15. The methodof claim 1 further comprising neutralizing the fabric in anacid-containing solution following treating with steam.
 16. The methodof claim 1, further comprising dyeing the fabric with a compositioncomprising a dye.
 17. A system for cationizing and dyeing a textileincluding a natural fiber or derivative thereof, the method comprising apadding bath for treating a textile including a natural fiber orderivative thereof configured to hold an aqueous solution comprising analkali metal hydroxide and a cationizing agent comprising a halogenatedcompound capable of generating two epoxide groups in the presence of thealkali metal hydroxide; and a steaming apparatus capable of treating thefabric in an environment comprising steam at a temperature in the rangeof greater than 100° C. to less than 110° C. for a period of time in therange of 1 min to 10 min to react the cationizing agent with the fabric.18. The system of claim 17 further comprising one or more of thefollowing: a roller mechanism for mechanically removing a portion of theaqueous solution from the fabric; a neutralization bath for neutralizingthe fabric in an acid-containing solution.
 19. The system of claim 17further comprising process controller allowing for the treatment withthe aqueous solution and the mechanical removal at one or moretemperatures of less than 35° C., and for a total a period of time ofnot greater than 1 minute.